Abstract:

A disclosed method of manufacturing a camera module includes providing an
optical assembly, providing an integrated circuit image capture device
(ICD), fixing the optical assembly directly to the ICD, then forming a
housing directly over the optical assembly. The method further includes
forming the housing over the ICD and the optical assembly via transfer
molding. The method further includes forming solder balls on the rear
surface of the ICD so as to enable the camera module to be reflow
soldered to a host device. In an alternative embodiment of the present
invention, the method includes providing a second ICD, providing a second
optical assembly, providing a housing substrate, fixing the first optical
assembly over the first ICD, fixing the second optical assembly over the
second ICD, and forming the housing substrate over both the first and
second optical assemblies. The alternative method further includes
separating the housing substrate in to a first portion formed over the
first optical assembly and second portion formed over the second optical
assembly, providing a second housing substrate, and forming the second
housing substrate over the first and second portions.

Claims:

1. A camera module comprising:an integrated circuit image capture device
including a set of contacts and an image sensor array, said contacts
facilitating an electrical connection between said camera module and a
camera module hosting device;an optical assembly mounted directly on said
image capture device; anda housing formed directly on said optical
assembly.

2. A camera module according to claim 1, wherein said camera module is
mountable directly to a circuit board of a camera hosting device via
reflow soldering.

3. A camera module according to claim 2, wherein said contacts of said
integrated circuit image capture device facilitate said reflow soldering
of said camera module to said circuit board of said camera hosting
device.

4. A camera module according to claim 3, wherein said contacts of said
integrated circuit image capture device each include a solder ball formed
thereon.

5. A camera module according to claim 1, wherein said housing is formed
via molding.

6. A camera module according to claim 5, wherein said housing is formed
directly over said optical assembly and said image capture device.

7. A camera module according to claim 1, wherein said optical assembly
includes a lens mounted over said image sensor array.

8. A camera module according to claim 1, wherein said optical assemble
includes a transparent substrate mounted over said image sensor array.

9. A camera module according to claim 8, wherein said optical assembly
further includes a lens stack mounted over said transparent substrate.

10. A camera module according to claim 9, wherein said housing is molded
directly over said lens stack.

11. A camera module according to claim 1, wherein said optical assembly is
a lens stack mounted directly on said integrated circuit image capture
device over said sensor array.

12. A camera module according to claim 11, wherein said housing is formed
directly on said lens stack via molding.

13. A method for manufacturing a camera module, said method
including:providing an integrated circuit image capture device;providing
an optical assembly;mounting said optical assembly directly to said
integrated circuit image capture device; andforming a housing over said
optical assembly after said optical assembly is mounted to said image
capture device.

14. A method for manufacturing a camera module according to claim 13,
wherein said step of providing an integrated circuit image capture device
includes providing an integrated circuit image capture device including a
set of contacts operable to facilitate the reflow soldering of said
camera module to a circuit board of a camera module hosting device.

15. A method for manufacturing a camera module according to claim 14, said
method further including forming solder balls on said contacts.

16. A method for manufacturing a camera module according to claim 13,
wherein said step of forming a housing over said optical assembly
includes molding said housing over said optical assembly.

17. A method for manufacturing a camera module according to claim 16,
wherein said step of forming a housing over said optical assembly further
includes forming said housing over said integrated circuit image capture
device.

18. A method for manufacturing a camera module according to claim 13,
wherein said step of mounting said optical assembly over said integrated
circuit image capture device further includes mounting a transparent
substrate over said sensor array of said integrated circuit image capture
device.

19. A method for manufacturing a camera module according to claim 18,
wherein said step of mounting said transparent substrate over said sensor
array includes adhering a rigid transparent substrate over said sensor
array.

20. A method for manufacturing a camera module according to claim 18,
wherein said step of mounting said transparent substrate over said sensor
array includes adhering a transparent substrate directly on said
integrated circuit image capture device.

21. A method for manufacturing a camera module according to claim 18,
wherein said step of mounting said transparent substrate over said
integrated circuit image capture device includes mounting a lens directly
over said sensor array.

22. A method for manufacturing a camera module according to claim 18,
wherein said step of mounting said optical assembly over said integrated
circuit image capture device includes providing a lens assembly and
mounting said lens assembly on said transparent substrate.

23. A method for manufacturing a camera module according to claim 22,
wherein said step of forming a housing over said optical assembly
includes molding a housing directly over said lens assembly and said
transparent substrate.

24. A method for manufacturing a camera module according to claim 23,
wherein said step of mounting said optical assembly further includes
mounting said optical assembly in a focused position before said step of
forming said housing on said optical assembly.

25. A method for manufacturing a camera module, said method
including:providing an integrated circuit image capture device;forming an
optical assembly directly on said integrated circuit image capture
device; andforming a housing directly over said optical assembly.

26. A method for manufacturing a camera module according to claim 25,
wherein said step of forming said optical assembly further includes
forming a focused optical assembly directly on said integrated circuit
image capture device before said step of forming said housing.

27. A method for manufacturing a camera module according to claim 25,
wherein said step of providing an image capture device further includes
forming a plurality of solder balls on said image capture device.

28. A method for manufacturing camera modules, said method
including:providing a first image capture device;providing a first
optical assembly;providing a second image capture device;providing a
second optical assembly;mounting said first optical assembly on said
first image capture device;mounting said second optical assembly on said
second image capture device;forming a housing substrate over said first
optical assembly and said second optical assembly after said first
optical assembly is mounted to said first image capture device and said
second optical assembly is mounted to said second image capture device;
andseparating said first housing substrate into a first portion and a
second portion after said first housing substrate is formed over said
first optical assembly and said second optical assembly, said first
portion of said first housing substrate forming a housing over said first
optical assembly, and said second portion of said first housing substrate
forming a housing over said second optical assembly.

29. A method for manufacturing camera modules according to claim 28, said
method further including:forming a second housing substrate over said
first portion of said first housing substrate, said first image capture
device, said second portion of said first housing substrate, and said
second image capture device.

30. A method for manufacturing camera modules according to claim 29, said
method further including forming a first set of solder balls on said
first image capture device and forming a second set of solder balls on
said second image capture device after said second housing substrate is
formed over said first portion of said first housing substrate, said
first image capture device, said second portion of said first housing
substrate, and said second image capture device.

31. A method for manufacturing camera modules according to claim 30, said
method further including separating said second housing substrate into a
first portion and a second portion after said first set of solder balls
are formed on said first image capture device and said second set of
solder balls are formed on said second image capture device, said first
portion of said second housing substrate being formed over said first
portion of said first housing substrate and said second portion of said
second housing substrate being formed over said second portion of said
first housing substrate.

32. A method for manufacturing camera modules according to claim 28, said
method further including forming a first set of solder balls on said
first image capture device and forming a second set of solder balls on
said second image capture device before said step of separating said
first housing substrate.

33. A method for manufacturing camera modules according to claim 28,
wherein said step of providing a first image capture device and said step
of providing said second image capture device include providing a unitary
integrated circuit substrate, said first image capture device and said
second image capture device being formed on said unitary integrated
circuit substrate.

34. A method for manufacturing camera modules according to claim 33, said
method further including separating said first image capture device from
said second image capture device after said first housing substrate is
formed over said first optical assembly and said second optical assembly.

35. A method for manufacturing camera modules according to claim 34,
wherein said step of separating said first housing substrate further
includes separating said first image capture device from said second
image capture device.

36. A method for manufacturing camera modules according to claim 34, said
method further including:molding a second housing substrate into a single
body formed over said first portion of said first housing substrate, said
first image capture device, said second portion of said first housing
substrate, and said second image capture device.

37. A method for manufacturing camera modules according to claim 36, said
method further including forming a first set of solder balls on said
first image capture device and forming a second set of solder balls on
said second image capture device after said second housing substrate is
formed over said first portion of said first housing substrate, said
first image capture device, said second portion of said first housing
substrate, and said second image capture device.

38. A method for manufacturing camera modules according to claim 37, said
method further including separating said second housing substrate into a
first portion and a second portion after said first set of solder balls
is formed on said first image capture device and said second set of
solder balls is formed on said second image capture device, said first
portion of said second housing substrate being formed over said first
portion of said first housing substrate and said second portion of said
second housing substrate being formed over said second portion of said
first housing substrate.

39. A method for manufacturing camera modules according to claim 28,
wherein:said steps of providing said first image capture device and said
second image capture device include providing an integrated circuit
substrate having a plurality of discrete image capture devices formed
thereon;said steps of providing said first optical assembly and said
second optical assembly include providing a plurality of pre-focused
optical stack assemblies;said steps of mounting said first optical
assembly to said first image capture device and mounting said second
optical assembly to said second image capture device include mounting
each of said plurality of pre-focused optical stack assemblies to a
respective one of said plurality of image capture devices; andsaid step
of forming said housing substrate over said first optical assembly and
said second optical assembly includes forming said housing substrate over
said plurality of focused optical assemblies after said step of mounting
said plurality of optical assemblies to said plurality of image capture
devices; andsaid step of separating said first housing substrate includes
separating said first housing substrate into a plurality of respective
discrete housing portions each formed over a respective one of said
plurality of pre-focused optical stack assemblies.

40. A method for manufacturing camera modules according to claim 39, said
method further including providing a second housing substrate and forming
said second housing substrate over said plurality of housing portions and
said plurality of said image capture devices.

41. A method for manufacturing camera modules according to claim 40, said
method further including forming a set of solder balls on each of said
plurality of image capture devices.

42. A method for manufacturing camera modules according to claim 41, said
method further including separating said second housing substrate into a
plurality of discrete camera modules after said step of forming a set of
solder balls on each of said plurality of image capture devices.

43. A method for manufacturing camera modules according to claim 28,
wherein said step of forming said first housing substrate over said first
optical assembly and said second optical assembly includes molding said
housing substrate into a single body formed directly over said first
optical assembly and said second optical assembly.

44. A camera module host device comprising:a printed circuit board; anda
camera module electrically connected to said printed circuit board, said
camera module including an image capture device, an optical assembly, and
a housing, said optical assembly being fixed directly to said image
capture device, said housing being formed directly on said optical
assembly.

45. A camera module host device according to claim 44, wherein said camera
module is reflow soldered to said printed circuit board.

46. A camera module hosting device according to claim 44, wherein said
camera module is mounted to said printed circuit board using pick and
place technology.

Description:

BACKGROUND OF THE INVENTION

[0001]1. Field of the Invention

[0002]This invention relates generally to electronic devices, and more
particularly to digital camera modules. Even more particularly, this
invention relates to a design for a simplified wafer level camera module
that can be reflow soldered to a hosting device.

[0005]Host device manufacturers prefer digital camera modules to be small,
so that they can be incorporated into the host device without increasing
the overall size of the host device. Further, host device manufacturers
prefer camera modules that minimally affect host device design. In
meeting these requirements the host device manufacturers prefer camera
modules that capture images of the highest possible quality. Of course,
it is an ongoing goal for camera module manufacturers to design camera
modules that meet these requirements at minimal manufacturing cost.

[0006]A conventional digital camera module generally includes a lens
assembly, a housing, a printed circuit board (PCB), and an integrated
image capture device (ICD). Typically, the components are formed
separately and later assembled to create the digital camera module. That
is, the ICD is attached to the PCB, and then the housing is attached to
the PCB so that the ICD is surrounded by the bottom of the housing. Then,
the lens assembly is mounted to the opposite end of the housing to focus
incident light onto an image capture surface of the ICD. Typically, the
lens assembly includes a sloped surface (e.g., threads, cam, ramps, etc.)
that engage a complementary sloped surface formed on the housing such
that proper focusing can be achieved by rotating the lens assembly within
the housing. After the lens assembly is properly displaced with respect
to the image capture surface, the lens assembly is fixed (e.g., via
adhesive, thermal weld, etc.) with respect to the housing. The ICD is
electrically coupled to the PCB, which includes a plurality of electrical
contacts for the ICD to communicate image data to the host device for
processing, display, and storage.

[0007]In manufacturing these camera modules, many problems are encountered
by the camera module manufacturers. As an example, bare ICD dies are
extremely vulnerable to contamination when exposed to contaminants such
as dust and/or other particulate debris. Further, ICDs are extremely
vulnerable when exposed to materials (e.g., adhesives) and processes
(e.g., housing attachment, molding, lens attachment, etc.) used in the
assembly of the camera modules. Contamination typically results in the
discarding of the defective image capture devices which can be extremely
expensive, especially when yield losses are high. To minimize
contamination, the camera modules are typically assembled in class 100
clean rooms. Although the image capture devices of assembled camera
modules are protected from contaminants outside of the camera module,
they are still vulnerable to internal contaminants. Such internal
contaminants are usually the result of trapped dust, adhesives, and/or
particulates formed by frictional wear within the camera module.
Frictional wear typically occurs during assembly processes such as
focusing. In particular, particles are formed when the sloped surface of
the lens assembly rubs against the sloped surface of the housing.
Contamination of an image sensor after the camera is assembled can be
especially expensive because the entire camera module may have to be
discarded.

[0008]Another challenge faced by camera module manufacturers is that the
components of camera modules are extremely small and, therefore, require
extremely delicate, and therefore expensive, processes for fabrication,
assembly, and alignment. Indeed, the alignment process becomes
increasingly more difficult as the number of required camera module
components is increased. This is because the strict position tolerances
between camera module components accumulate proportionally with the
number of components coupling the image capture surface to the lenses.
Ideally, the lenses should all be coaxially perpendicular to the center
of the planar image capture surface. However, this is typically only
achieved within a predetermined overall tolerance defined by the sum of:
the tolerance of the ICD with respect to the PCB, the tolerance of the
PCB with respect to the housing, the tolerance of the housing with
respect to the focus/zoom device, and the tolerances of the lenses with
respect to the focus/zoom device.

[0009]As yet another example problem, camera modules typically cannot be
reflow soldered to host devices without damaging the camera module.
Reflow soldering is a very well developed and efficient electronic
manufacturing process. Therefore, it would be desirable to be able to use
a reflow solder process to attach camera modules to host devices.
However, known devices cannot withstand reflow solder attachment.

[0010]What is needed, therefore, is a camera module that is less
vulnerable to contamination of the image capture surface. What is also
needed is a camera module that can be assembled with a more forgiving
tolerance between the lenses and the image capture surface. What is also
needed is a camera module that requires fewer components and fewer
manufacturing steps. What is also needed is a camera module that can
withstand a reflow soldering process.

SUMMARY

[0011]The present invention overcomes the problems associated with the
prior art by providing a wafer level camera module capable of
withstanding a solder reflow process. The invention facilitates the
mounting of the camera modules to printed circuit boards of host devices
using a conventional reflow solder process.

[0012]An example camera module includes an integrated circuit image
capture device, and optical assembly and a housing. The image capture
device includes a set of electrical contacts and an image sensor array.
The contacts facilitate an electrical connection between the camera
module and a camera module hosting device. For example, the camera module
is mountable directly to a circuit board of a camera hosting device using
solder balls and a reflow soldering process.

[0013]The optical assembly is mounted directly on the image capture
device, and the housing is formed directly on the optical stack. The
housing is formed, for example, via molding directly over the optical
assembly and the image capture device. The optical assembly includes a
lens mounted over the image sensor array. Optionally, the optical
assemble includes a transparent substrate mounted over said image sensor
array and a lens stack mounted over the transparent substrate. In another
embodiment, the optical assembly is a lens stack that is mounted directly
on the integrated circuit image capture device over the sensor array. In
either case, the housing is formed directly over the lens stack via
molding.

[0014]Methods for manufacturing a camera module are also disclosed. An
example method includes providing an integrated circuit image capture
device, providing an optical assembly, mounting the optical assembly
directly to the integrated circuit image capture device, and forming a
housing over the optical assembly after the optical assembly is mounted
to the image capture device. The step of providing an integrated circuit
image capture device includes providing an integrated circuit image
capture device including a set of contacts operable to facilitate the
reflow soldering of the camera module to a circuit board of a camera
module hosting device. The method further includes forming solder balls
on the contacts.

[0015]The step of forming a housing over the optical assembly includes
molding the housing over the optical assembly and over the integrated
circuit image capture device.

[0016]Optionally, the step of mounting the optical assembly over the
integrated circuit image capture device includes mounting a transparent
substrate over the sensor array of the integrated circuit image capture
device. In a particular example, mounting the transparent substrate over
sensor array includes adhering a rigid transparent substrate over the
sensor array. The transparent substrate can be adhered directly on the
integrated circuit image capture device.

[0017]As another option, the step of mounting the transparent substrate
over the integrated circuit image capture device includes mounting a lens
directly over the sensor array. In this case, the step of mounting the
optical assembly over the integrated circuit image capture device
includes providing a lens assembly and mounting the lens assembly on the
transparent substrate. the step of forming a housing over the optical
assembly includes molding a housing directly over the lens assembly and
the transparent substrate. In addition, the step of mounting the optical
assembly further includes mounting the optical assembly in a focused
position before the step of forming the housing on said optical assembly.

[0018]Another example method for manufacturing a camera module is
disclosed. The method includes providing an integrated circuit image
capture device, forming an optical assembly directly on said integrated
circuit image capture device, and forming a housing directly over said
optical assembly. The step of forming the optical assembly includes
forming a pre-focused optical assembly (e.g., an optical stack) directly
on the integrated circuit image capture device before the step of forming
said housing. The step of providing the image capture device includes
forming a plurality of solder balls on the image capture device.

[0019]An example method for simultaneously manufacturing a plurality of
camera modules is also disclosed. The method includes providing a first
image capture device, providing a first optical assembly, providing a
second image capture device, providing a second optical assembly,
mounting the first optical assembly on the first image capture device,
mounting the second optical assembly on the second image capture device,
forming a housing substrate over the first optical assembly and the
second optical assembly after the first optical assembly is mounted to
the first image capture device and the second optical assembly is mounted
to the second image capture device, and separating the first housing
substrate into a first portion and a second portion after the first
housing substrate is formed over the first optical assembly and the
second optical assembly. The first portion of the first housing substrate
forms a housing over the first optical assembly, and the second portion
of the first housing substrate forms a housing over the second optical
assembly. Optionally, the method further includes forming a second
housing substrate over the first portion of the first housing substrate,
the first image capture device, the second portion of the first housing
substrate, and the second image capture device. In addition, the method
further includes forming a first set of solder balls on the first image
capture device and forming a second set of solder balls on the second
image capture device. The solder balls can be advantageously formed on
the image capture devices after the second housing substrate is formed
over the first portion of the first housing substrate, the first image
capture device, the second portion of the first housing substrate, and
the second image capture device. The example method further includes
separating the second housing substrate into a first portion and a second
portion after the first set of solder balls are formed on the first image
capture device and the second set of solder balls are formed on the
second image capture device. The first portion of the second housing
substrate is formed over the first portion of the first housing
substrate, and the second portion of the second housing substrate is
formed over the second portion of the first housing substrate.
Alternatively, the step of forming a first set of solder balls on the
first image capture device and forming a second set of solder balls on
the second image capture device can be performed before the step of
separating the first housing substrate.

[0020]In a disclosed method, the step of providing the first image capture
device and the step of providing the second image capture device include
providing a unitary integrated circuit substrate. The first image capture
device and the second image capture device are formed on the unitary
integrated circuit substrate. For example, the first and second image
capture devices are discrete integrated circuits in a unitary silicon
wafer. The method further includes separating the first image capture
device from the second image capture device after the first housing
substrate is formed over the first optical assembly and the second
optical assembly. The step of separating the first housing substrate
includes separating the first image capture device from the second image
capture device.

[0021]Optionally, the method further includes molding a second housing
substrate into a single body formed over the first portion of the first
housing substrate, the first image capture device, the second portion of
the first housing substrate, and the second image capture device. The
method further includes forming a first set of solder balls on the first
image capture device and forming a second set of solder balls on the
second image capture device. The solder balls are formed after the second
housing substrate is formed over the first portion of the first housing
substrate, the first image capture device, the second portion of the
first housing substrate, and the second image capture device. The method
further includes separating the second housing substrate into a first
portion and a second portion after the first set of solder balls is
formed on the first image capture device and the second set of solder
balls is formed on the second image capture device. The first portion of
said second housing substrate is formed over the first portion of the
first housing substrate, and the second portion of the second housing
substrate is formed over the second portion of the first housing
substrate.

[0022]In general, the manufacturing method can be applied to a wafer
including a great plurality of image capture devices formed therein. In
such a case, the steps of providing the first image capture device and
the second image capture device include providing an integrated circuit
substrate having a plurality of discrete image capture devices formed
thereon. The steps of providing the first optical assembly and the second
optical assembly include providing a plurality of pre-focused optical
stack assemblies. The steps of mounting the first optical assembly to the
first image capture device and mounting the second optical assembly to
the second image capture device include mounting each of the plurality of
pre-focused optical stack assemblies to a respective one of the plurality
of image capture devices. In addition, the step of forming the housing
substrate over the first optical assembly and the second optical assembly
includes forming the housing substrate over the plurality of focused
optical assemblies after the step of mounting the plurality of optical
assemblies to the plurality of image capture devices, and the step of
separating the first housing substrate includes separating the first
housing substrate into a plurality of respective discrete housing
portions, each formed over a respective one of the plurality of
pre-focused optical stack assemblies. Optionally, the method further
includes providing a second housing substrate material and forming a
second housing substrate over the plurality of housing portions and the
plurality of said image capture devices.

[0023]The method further includes forming a set of solder balls on each of
the plurality of image capture devices. The second housing substrate is
separated into a plurality of discrete camera modules, after the step of
forming a set of solder balls on each of the image capture devices.

[0024]A camera module host device is also disclosed. The host device
includes a printed circuit board and a camera module electrically
connected to the printed circuit board. The camera module includes an
image capture device, an optical assembly, and a housing. The optical
assembly is fixed directly to said image capture device, and the housing
is formed directly on the optical assembly. The camera module is mounted
to the printed circuit board using pick and place technology and then
reflow soldered to the printed circuit board.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]The present invention is described with reference to the following
drawings, wherein like reference numbers denote substantially similar
elements:

[0026]FIG. 1 is a perspective view of a camera module mounted on a printed
circuit board of a host device;

[0027]FIG. 2 is a partially sectioned, perspective view of the camera
module of FIG. 1;

[0028]FIG. 3 is a partially sectioned, perspective view of a wafer level
package of the camera module of FIG. 1;

[0029]FIG. 4 is a cross-sectional side view of the camera module of FIG.
1;

[0030]FIG. 5 is a partially sectioned view of an alternative camera
module;

[0031]FIG. 6 is a perspective view of an image capture device wafer used
to form a plurality of camera modules like the camera module of FIG. 5;

[0032]FIG. 7 is a perspective view of a housing substrate formed over the
image capture device wafer of FIG. 6;

[0033]FIG. 8 is a perspective view of an array of individual packages,
including the camera module of FIG. 5, mounted on a rigid carrier plate
to form a manufacturing work piece;

[0034]FIG. 9 is a perspective view of a second housing substrate formed
over the individual packages of FIG. 8.

[0035]FIG. 10 is a rear perspective view of the housing substrate of FIG.
9;

[0036]FIG. 11 is a flow chart summarizing a method for manufacturing a
camera module; and

[0037]FIG. 12 is a flow chart summarizing a method for manufacturing a
plurality of camera modules.

DETAILED DESCRIPTION

[0038]The present invention overcomes the problems associated with the
prior art, by providing a simplified wafer level camera module that can
withstand reflow soldering conditions. In the following description,
numerous specific details are set forth (e.g., number of lenses, type of
epoxy, etc.) in order to provide a thorough understanding of the
invention. Those skilled in the art will recognize, however, that the
invention may be practiced apart from these specific details. In other
instances, details of well known electronic assembly practices and
equipment have been omitted, so as not to unnecessarily obscure the
present invention.

[0039]FIG. 1 is a perspective view of a camera module 100 according to one
embodiment of the present invention. Camera module 100 is shown mounted
on a portion of a printed circuit board (PCB) 102 that represents a main
PCB of a camera hosting device (e.g., cell phone, PDA, etc.). Camera
module 100 communicates electrically with other components of the hosting
device via a plurality of conductive traces 104. Device 106 represents an
electronic component (e.g., passive component) that may be mounted
directly on PCB 102. Those skilled in the art will recognize that the
particular design of PCB 102 will depend on the particular application,
and is not particularly relevant to the present invention. Therefore, PCB
102, traces 104, and device 106 are representational in character only.

[0040]FIG. 2 is a partially sectioned perspective view of camera module
100. In this particular embodiment, camera module 100 includes a housing
200 formed directly over a wafer level package (WLP) 202. In particular,
housing 200 is transfer molded directly over WLP 202, thus yielding
camera module 100. Housing 200 is formed from a rigid opaque material
(e.g., moldable plastic) that provides structural support to camera
module 100 while preventing stray light from passing therethrough.
Housing 200 is formed to include an optical aperture 204 to expose an
image capture surface of WLP 202 to light.

[0041]WLP 202 includes an optical assembly 206 mounted directly on an
image capture device (ICD) 208. Optical assembly 206 includes a
transparent substrate 210 and a lens stack 212 mounted over ICD 208.
Transparent substrate 210 is fixed to ICD 208 by some suitable means such
as an optical grade epoxy. Likewise, lens stack 212 is fixed to
transparent substrate 210 by some suitable means such as an optical grade
epoxy disposed therebetween. Optical assembly 206 will be further
discussed with reference to FIG. 3.

[0042]FIG. 3 is a partially sectioned perspective view of WLP 202, which
is formed by mounting optical assembly 206 directly over ICD 208. ICD 208
includes a top surface 300 and a bottom surface 302. Top surface 300
includes a sensor array 304 operative to convert optical images into
electronic signals. Top surface 300 also provides a base to receive
optical assembly 206. Bottom surface 302 includes a plurality of
electrical contacts 400 (shown in FIG. 4) to facilitate electronic
communication between camera module 100 and PCB 102.

[0043]Transparent substrate 210 is mounted (e.g., with an optical
adhesive) on top surface 300 to protect sensor array 304 from
contamination during subsequent manufacturing steps. As an alternative,
transparent substrate 210 can be omitted and lens stack 212 can be
mounted directly over image sensor array 304. As another alternative, WLP
202 could be a cavity package, wherein transparent substrate 210 would be
slightly elevated off of ICD 208 so as to form an air gap therebetween.

[0044]After transparent substrate 210 is fixed to ICD 208, lens stack 212
is fixed to the opposite surface of transparent substrate 210. Lens stack
212 can be formed via wafer level processing technologies (e.g., plasma
etching, replication, etc.) known to those skilled in the art.

[0045]It is important to recognize that no focus mechanism is required
and, therefore, none is provided. The reason for this is that the wafer
level assembly of optical assembly 206 and the direct attachment of
optical assembly 206 to ICD 208 are very precise. In addition, the
tolerance stack up (accumulation) suffered by prior art devices is
effectively minimized.

[0046]FIG. 4 is a cross-sectional side view of camera module 100. As shown
in this particular embodiment, bottom surface 302 of ICD 208 includes a
plurality of electrical contacts 400 which facilitate mounting and the
exchange of data between camera module 100 and a host device. In this
particular embodiment, contacts 400 are solder balls, which enable camera
module to be connected to a host PCB via conventional surface mount
technology (e.g., pick and place, reflow, etc.). Also, in this example
embodiment, housing 200 wraps around the edges and contacts the bottom
surface 302 of ICD 208. It is important to note that camera module 100
can be reflow soldered directly on to the PCB of a hosting device.

[0047]FIG. 5 is a partially sectioned perspective view of an alternative
camera module 500. In this particular embodiment, camera module 500
includes a housing 502 formed over a wafer level package (WLP) 504.
Housing 502 includes an inner layer 506 and an outer layer 508 formed
during separate manufacturing processes that will be further discussed
with reference to subsequent figures. Inner layer 506 is a rigid opaque
material (e.g., moldable plastic) transfer molded directly over WLP 504
so as to provide structural support to WLP during manufacturing
processes. Similarly, outer layer 508 is a rigid opaque material transfer
molded directly over inner layer 506 and around the sides of WLP 504 to
provide structural support to camera module 500 while preventing stray
light from passing therethrough. During the molding of inner layer 506
and outer layer 508, two optical apertures 510 and 512, respectively, are
left to facilitate the focusing of an image onto a sensor array of ICD
516.

[0048]WLP 504 includes a lens stack 514 mounted over image capture device
(ICD) 516. In particular, lens stack 514 is fixed directly onto the top
surface of ICD 516 via an optical grade epoxy. Likewise, the individual
lenses of lens stack 514 are fixed to one another in a focused position
via optical grade epoxy. The rear surface of ICD 516 includes set of
solder balls 518 formed thereon to facilitate the electrical connection
between camera module 500 and a hosting device. Because of the
substantial similarity to ICD 208, details of ICD 516 will not be
discussed in any greater detail at this point.

[0049]FIG. 6 is a perspective view of an array of individual lens stacks
514 mounted on an integrated circuit ICD wafer 600, so as to form a
plurality of individual WLPs 504. ICD wafer 600 includes an array of
discrete integrated ICD circuits 602 which, upon separation, yield
individual image capture devices 516. In this particular embodiment, each
lens stack 514 is formed and then individually mounted over a respective
one of ICD circuits 602 in a focused position such that no further
focusing processes are needed. Note that three of lens stacks 514 are
shown exploded from wafer 600 to show ICD circuits 602 positioned
thereunder. It is important to recognize that ICD circuits 602, and
therefore lens stacks 514, are spaced apart from one another sufficient
to allow the separation wafer 600 into individual WLPs 504, but are
positioned as close as possible to conserve area on the silicon wafer.

[0050]During the mounting of lens stacks 514, optical grade epoxy is
dispensed and evenly distributed across wafer 602. Then, each individual
lens stack 514 is precisely placed over a respective one of ICD circuits
602 using, for example, pick-and-place equipment. Once lens stacks 514
are correctly positioned on wafer 600, the epoxy undergoes a curing
process (e.g., UV exposure) until stacks 514 are fixed to wafer 602 in
preparation for subsequent manufacturing processes.

[0051]FIG. 7 shows a partially sectioned, perspective view of a housing
substrate 700 formed over lens stacks 514 and wafer 600, which forms
inner layer 506. In this particular embodiment, housing substrate 700 is
an opaque material (e.g., moldable plastic, thermosetting resin, etc.)
that is uniformly transfer-molded directly over lens stacks 514 and the
top surface of wafer 600. As substrate 700 is molded over the top surface
of wafer 600, the adjacent spaces between lens stacks 514 become filled
in with substrate 700. As substrate 700 is molded over lens stacks 514,
an array of plungers (not shown) of a transfer molding machine contact
the top surfaces of each lens stack 514 to form optical apertures 510.
After housing substrate 700 is formed over lens stacks 514 and wafer 600,
housing substrate 700 is cured (e.g., cooled). Then, housing substrate
700 and wafer 600 are diced along lines 702 to yield individual packages
800 (shown in FIG. 8). After packages 800 are formed, they are cleaned
and prepared to be temporarily mounted on a carrier plate 802 (also shown
in FIG. 8).

[0052]FIG. 8 is a perspective view of an array of individual packages 800
temporarily mounted on a rigid carrier plate 802. At this point in the
manufacturing process, outer layer 508 is not yet formed and, therefore,
the outer most layer of packages 800 is actually inner layer 506. In this
particular embodiment, individual packages 800 are individually
positioned on carrier plate 802 using pick-and-place technology, which is
well known to those skilled in the art. Packages 800 are positioned with
respect to one another such that there is an even space between adjacent
individual packages 800. Individual packages 800 are held in a fixed
position on carrier plate 802 via an adhesive substrate (e.g., tape) 804
in preparation of forming respective outer layers 508 of housing 502 on
each individual package 800.

[0053]FIG. 9 shows a perspective view of a second housing substrate 900
formed directly over packages 800 and adhesive substrate 804. In this
particular embodiment, housing substrate 900 is an opaque material (e.g.,
moldable plastic, thermosetting resin, etc.) that is uniformly
transfer-molded directly over packages 800 and the top surface of
adhesive substrate 804 so as to form an outer layer 508 over each one of
respective packages 800. As substrate 900 is molded over the top surface
of adhesive substrate 804, the adjacent spaces between packages 800
become filled in with substrate 900, thus covering the diced side edge
surfaces of each one of image capture devices 516. By covering the side
edge surfaces of each image capture device 516 with substrate 900, stray
light is even more effectively prevented from entering package 800. As
substrate 900 is molded over packages 800, an array of optical apertures
512 are coaxially formed over respective optical apertures 510, using a
similar technique as described above. After housing substrate 900 is
formed over packages 800, housing substrate 900 is cured (e.g., cooled)
until rigid. Then, substrate 900 is removed from carrier plate 802 and
adhesive substrate 804 is removed from substrate 900 in preparation for
subsequent processes.

[0054]FIG. 10 shows a rear perspective view of substrate 900 formed over
packages 800. At this point in the manufacturing process, adhesive
substrate 804 has been removed from housing substrate 900 to expose rear
surfaces 1002 of each one of respective image capture devices 516. Each
of rear surfaces 1002 includes a respective set of electrical contacts
(not shown) formed thereon. These electrical contacts are in electrical
communication with the circuitry formed in the top layer ICD 516 by, for
example, through silicon vias.

[0055]After the removal of adhesive substrate 804, substrate 900 remains
in one solid piece and positioned face-down while individual sets of
solder balls 518 are mounted to the respective sets of electrical
contacts. Once solder balls 518 are mounted over respective electrical
contacts, solder balls 518 are reflowed onto the respective sets of
electrical contacts. After solder balls 518 are reflowed, substrate 900
is diced (e.g., sawed) along lines 904 to form individual outer layers
508 over each respective package 800. Of course, once the dicing of
substrate 900 is completed, multiple individual camera modules 500 are
formed.

[0056]FIG. 11 is a flow chart summarizing one method 1100 of manufacturing
a camera module according to the present invention. In a first step 1102,
an image capture device is provided. Next, in a second step 1104, an
optical assembly is provided. Then, in a third step 1106, the optical
assembly is fixed to the image capture device. Finally, in a fourth step
1108, a camera housing is formed directly on the optical assembly.

[0057]FIG. 12 is a flow chart summarizing an example method 1200 of
manufacturing camera modules according to the present invention. In a
first step 1202, a first image capture device is provided. Next, in a
second step 1204, a first optical assembly is provided. Then, in a third
step 1206, a second image capture device is provided. Next, in a fourth
step 1208, a second optical assembly is provided. Then, in a fifth step
1210, a first housing substrate material is provided. Next, in a sixth
step 1212, the first optical assembly is mounted to the first image
capture device. Then, in a seventh step 1214, the second optical assembly
is mounted to the second image capture device. Next, in an eighth step
1216, the first housing substrate is formed over both the first optical
assembly and the second optical assembly. Finally, in a ninth step 1218,
the first housing substrate is separated into a first portion and a
second portion.

[0058]The description of particular embodiments of the present invention
is now complete. Many of the described features may be substituted,
altered or omitted without departing from the scope of the invention. For
example, different numbers of lens elements may be used to form the
optical stacks mounted on the ICDs. As another example, an IR filter can
be integrated in the optical glass used to form the optical stacks,
thereby reducing the number of components and assembly steps needed to
complete the module. These and other deviations from the particular
embodiments shown will be apparent to those skilled in the art,
particularly in view of the foregoing disclosure.